Selective and flexible production of synthetic gasoline

ABSTRACT

A production plant and a method for production of a synthetic gasoline product from a synthetic hydrocarbon mixture produced by post-treatment of a synthetic gasoline product including less than a specified concentration of olefins, such as 6 vol % or 11 vol % from a first synthetic hydrocarbon mixture produced from a mixture of reactive oxygenates, the first synthetic hydrocarbon mixture having T90 of less than 140° C. and including at least the specified concentration of olefins and a second synthetic hydrocarbon mixture, produced from a mixture of reactive oxygenates, the second synthetic hydrocarbon mixture having T90 of more than 150° C., the method including: a. directing the second synthetic hydrocarbon mixture to contact a material catalytically active in hydrocracking under effective hydrocracking conditions, to provide a hydrocracked second synthetic hydrocarbon mixture, b. directing the first synthetic hydrocarbon mixture to contact a material catalytically active in olefin hydrogenation, to provide a hydrogenated hydrocarbon mixture.

The present invention relates to a method and a process plant forflexible production of a gasoline product with a low amount of highboiling hydrocarbons and olefins from methanol and other oxygenates,which optionally may be produced from synthesis gas.

Production of synthetic gasoline from methanol and other easilyconvertible oxygenates either produced via synthesis gas of fossil orrenewable origin or of other origins (commonly known as the methanol togasoline, MTG, process), results in a product having manycharacteristics highly suitable for gasoline, but having a distillationcurve, which compared to typical fractionated fossil feedstock,comprises a distillation tail rich in diaromatic hydrocarbons, e.g.,substituted naphthalenes, and other two-ring structures, e.g.,substituted indenes, which have a tendency to formation of depositsand/or particle emissions during combustion in a vehicle engine.Furthermore, the synthetic gasoline comprises an amount of olefins andaromatics. This product distribution from the MTG process is dictated bykinetics and equilibrium, and may be close to or in conflict withregulations on boiling points and concentrations of regulatedconstituents in gasoline, and the nature of the MTG process onlyprovides few possibilities for adjusting the product distribution. Theheaviest product fraction could be removed by fractionation and used forfuel oil in the process, however, this option is associated with a lossof profit, so instead there is a need for a chemical solution to thisproblem.

Recent regulations for gasoline specifications in various jurisdictionsinclude upper limits for T₉₀ of 152° C. (305° F.) and less than 6 vol %olefins in strict specifications or T₉₀ of 168° C. (335° F.) and lessthan 10 vol % olefins in intermediate specifications in contrast tocommonly T₉₀ of 190° C. (375° F.) and less than 18 vol % olefins inprior specifications.

Some such specifications are indirect, by specifying properties afterblending, e.g. with ethanol. For convenience, the examples ofspecifications will be referred to throughout the present applicationunder the terms strict specifications and intermediate specifications,without implying any legal compliance with specific regulations, unlessexpressly stated.

Since synthetic gasoline from a production plant may be distributed todifferent markets, with different gasoline specifications, there is aneed for a production process which provides flexibility for theproduction plant.

In the following the term effective conditions of a reaction shall beused to signify conditions, such as pressure, temperature and spacevelocity, under which the conversion by said reaction is at least 10%,unless otherwise stated.

In the following the term ppmw shall be used to signify weight parts permillion.

In the following the term wt % this shall be used to signifyweight/weight %.

In the following the term vol % this shall be used to signify vol/vol %.

In the following the term Cn shall be used to signify hydrocarbons withexactly n carbon atoms, e.g. C10 signifies hydrocarbons with exactly 10carbon atoms. Similarly, Cn+ shall be used to signify hydrocarbons withat least n carbon atoms, e.g. C10+ signifies hydrocarbons with at least10 carbon atoms In general, boiling points are determined according toASTM D86, unless otherwise specified. In this respect T_(n) shall beused to signify the temperature at which n vol % has been distilled inthe equipment defined by ASTM D86, e.g. T₉₀ is the temperature at which90 vol % of the hydrocarbon mixture has been distilled.

In the following, a synthetic hydrocarbon mixture produced from amixture of reactive oxygenates may be understood as a hydrocarbonaceousmixture wherein at least 50% of the C9 aromatics present in saidhydrocarbonaceous mixture are tri-methyl benzenes.

A broad aspect of the present disclosure relates to a method forproviding a synthetic gasoline product comprising less than a specifiedconcentration of olefins, such as 6 vol % or 11 vol % from a firstsynthetic hydrocarbon mixture produced from a mixture of reactiveoxygenates, said first synthetic hydrocarbon mixture having T90 of lessthan 140° C. and comprising at least said specified concentration ofolefins and a second synthetic hydrocarbon mixture, produced from amixture of reactive oxygenates, said second synthetic hydrocarbonmixture having T90 of more than 150° C. said method comprising the stepsof

-   -   a. directing the second synthetic hydrocarbon mixture to contact        a material catalytically active in hydrocracking under effective        hydrocracking conditions, to provide a hydrocracked second        synthetic hydrocarbon mixture,    -   b. directing said first synthetic hydrocarbon mixture to contact        a material catalytically active in olefin hydrogenation, to        provide a hydrogenated hydrocarbon mixture,        -   wherein said hydrocracked second synthetic hydrocarbon            mixture is either added to the first synthetic hydrocarbon            mixture upstream contacting said material catalytically            active in olefin hydrogenation or it is added to            hydrogenated hydrocarbon mixture, downstream contacting said            material catalytically active in olefin hydrogenation to            provide said synthetic gasoline product.

This has the associated benefit of enabling a flexible production ofsynthetic gasoline adhering to strict specifications or intermediatespecifications for boiling point and concentration of olefins asrequired.

In a further embodiment effective hydrocracking conditions involve atemperature in the interval 250-425° C., a pressure in the interval30-150 Bar, and a liquid hourly space velocity (LHSV) in the interval0.5-4, optionally together with intermediate cooling by quenching withhydrogen, feed or product and wherein the material catalytically activein hydrocracking comprises (a) one or more active metals taken from thegroup platinum, palladium, nickel, cobalt, tungsten and molybdenum, (b)an acidic support showing cracking activity, such as amorphous acidicoxides and molecular sieves and (c) a refractory support such asalumina, silica or titania, or combinations thereof. This has theassociated benefit of such conditions being effective for hydrocrackingof synthetic gasoline. Typically, the conditions are chosen such thatthe amount of material boiling above 190° C. in said hydrocrackedhydrocarbon stream fraction is reduced by at least 20% wt, 50% wt or 80%wt or more compared to said hydrocracker feed stream.

In a further embodiment effective hydrogenation conditions involve atemperature in the interval 220-350° C., a pressure in the interval30-150 Bar, and a liquid hourly space velocity (LHSV) in the interval0.5-4, optionally together with intermediate cooling by quenching withhydrogen, feed or product and wherein the material catalytically activein hydrocracking comprises 0.1% to 30% of one or more active metalstaken from the group platinum, palladium, nickel, cobalt, tungsten andmolybdenum and a refractory support such as alumina, silica or titania,or combinations thereof, such as 5-20 wt % sulfided molybdenum ortungsten and 1-10 wt % sulfided nickel or cobalt on an alumina support.This has the associated benefit of such conditions being effective forhydrogenations of olefins in synthetic gasoline. Typically, theconditions are chosen such that the amount of olefins is reduced by from20% wt to 80% wt or more compared to the feed stream to thehydrogenation unit.

In a further embodiment said one or more active metals of said materialcatalytically active in hydrocracking are taken from the groupconsisting of nickel, cobalt, tungsten and molybdenum and thehydrocracking feedstock contacting the material catalytically active inhydrocracking comprises at least 50 ppmw sulfur. This has the associatedbenefit of such a material catalytically active in hydrocracking havinga low cost.

In a further embodiment said one or more active metals of said materialcatalytically active in hydrocracking are taken from the groupconsisting of platinum and palladium and the hydrocracking feedstockcontacting the material catalytically active in hydrocracking comprisesat less than 50 ppmw sulfur. This has the associated benefit of such amaterial catalytically active in hydrocracking having a highselectivity.

In a further embodiment said one or more active metals of said materialcatalytically active in isomerization are taken from the groupconsisting of nickel, cobalt, tungsten and molybdenum and thehydrocracking feedstock comprises at least 50 ppmw sulfur. This has theassociated benefit of such a material catalytically active inisomerization having a low cost.

In a further embodiment said one or more active metals of said materialcatalytically active in isomerization are taken from the groupconsisting of nickel, platinum and palladium and the hydrocrackingfeedstock comprises at less than 50 ppmw sulfur. This has the associatedbenefit of such a material catalytically active in isomerization havinga high selectivity.

In a further embodiment said first synthetic hydrocarbon mixture andsaid second synthetic hydrocarbon mixture are provided by fractionationof a synthetic hydrocarbon mixture produced from a mixture of reactiveoxygenates, optionally after one or both synthetic hydrocarbon mixtureshaving contacted a material catalytically active in a hydroprocessingprocess under active hydroprocessing conditions. This has the associatedbenefit of enabling a flexible production of synthetic gasoline adheringto strict specifications or intermediate specifications, based on aseparation commonly carried out already in the stabilization of thesynthetic gasoline.

In a further embodiment said fractionation provides a third synthetichydrocarbon mixture, having a T90 above that of said second synthetichydrocarbon mixture and wherein said third synthetic hydrocarbon mixtureis directed to contact a material catalytically active in hydrocrackingunder active hydrocracking conditions, to provide a hydrocracked thirdsynthetic hydrocarbon mixture, which is included in said syntheticgasoline product, either by addition upstream said fractionation or byaddition in a position downstream said fractionation. This has theassociated benefit of further hydrocracking an amount of syntheticgasoline under mild conditions, ensuring a product adhering to strictspecifications or intermediate specifications, while minimizing theyield loss.

In a further embodiment said hydrocracking process conditions for thehydrocracking feedstock are chosen, such that the molar ratio betweenhydrocarbons comprising exactly 10 carbon atoms in the hydrocrackedhydrocarbon stream and the hydrocracking feedstock is less than 20%.This has the associated benefit of such a high hydrocracking conversionsimplifying the process by avoiding operation with recycle.

In a further embodiment the conditions of the hydrocracking step for thehydrocracking feedstock and the amount of recycled hydrocarbon streamare such that the ratio of the mass of hydrocarbons comprising at least11 carbon atoms in the synthetic gasoline to the mass of hydrocarbonscomprising at least 11 carbon atoms in the synthetic hydrocarbon mixtureis less than 5%. This has the associated benefit of a recycle processbeing able to obtain high overall hydrocracking conversion butmaintaining moderate conditions and thus moderate conversion per pass.

A further aspect of the present disclosure relates to a method forproduction of a synthetic gasoline product from a synthetic hydrocarbonmixture produced from a mixture of reactive oxygenates comprising thesteps of

-   -   i. fractionating the synthetic hydrocarbon mixture in at least a        low boiling hydrocarbon fraction and an intermediate boiling        hydrocarbon fraction,    -   ii. directing at least an amount of said intermediate boiling        hydrocarbon fraction to contact a material catalytically active        in isomerization under effective isomerization conditions to        provide an isomerized intermediate boiling hydrocarbon fraction,    -   iii. directing at least an amount of said isomerized        intermediate boiling hydrocarbon fraction to contact a material        catalytically active in hydrocracking under effective        hydrocracking conditions to provide a hydrocracked intermediate        boiling hydrocarbon fraction,    -   iv. combining at least an amount of said low boiling hydrocarbon        fraction with said hydrocracked intermediate boiling hydrocarbon        fraction to provide a hydrogenation feed stream and directing        this hydrogenation feed stream to contact a material        catalytically active in hydrogenation under effective        hydrogenation conditions providing a hydrogenated hydrocarbon        product stream.

This has the associated benefit of enabling a flexible production ofsynthetic gasoline adhering to strict specifications or intermediatespecifications, based in a process integrated with the stabilization ofsynthetic gasoline, wherein the amount of psedocumene in said isomerizedhydrocarbon stream is reduced by at least 20% wt, 50% wt or 80% wt ormore compared to said intermediate boiling hydrocarbon fraction.

In a further embodiment the method further comprises the steps of

-   -   v. further separating the synthetic hydrocarbon mixture in a        higher boiling fraction comprising at least 70% of the molecules        comprising 10 or more carbon atoms present in the hydrocarbon        mixture,    -   vi. directing at least an amount of said higher boiling        hydrocarbon fraction as a hydrocracking feedstock to contact a        material catalytically active in hydrocracking under effective        hydrocracking conditions providing a hydrocracked hydrocarbon        stream and    -   vii. separating said hydrocracked hydrocarbon stream, in the        same or an additional separation step, to provide a high boiling        hydrocracked hydrocarbon stream and an intermediate boiling        hydrocracked hydrocarbon stream,    -   wherein at least an amount of said intermediate boiling        hydrocracked hydrocarbon stream, is added to at least an amount        of either said intermediate boiling hydrocarbon fraction or said        isomerized intermediate boiling hydrocarbon fraction.

This has the associated benefit of further hydrocracking an amount ofsynthetic gasoline with high overall hydrocracking conversion butmaintaining moderate conditions and thus moderate conversion per pass,ensuring a product adhering to strict specifications or intermediatespecifications, while minimizing the yield loss.

In a further embodiment effective hydrocracking conditions involve atemperature in the interval 250-425° C., a pressure in the interval30-150 Bar, and a liquid hourly space velocity (LHSV) in the interval0.5-4, optionally together with intermediate cooling by quenching withhydrogen, feed or product and wherein the material catalytically activein hydrocracking comprises (a) one or more active metals taken from thegroup platinum, palladium, nickel, cobalt, tungsten and molybdenum, (b)an acidic support showing cracking activity, such as amorphous acidicoxides and molecular sieves and (c) a refractory support such asalumina, silica or titania, or combinations thereof. This has theassociated benefit of such conditions being effective for hydrocrackingof synthetic gasoline. Typically, the conditions are chosen such thatthe amount of material boiling above 190° C. in said hydrocrackedhydrocarbon stream fraction is reduced by at least 20% wt, 50% wt or 80%wt or more compared to said hydrocracker feed stream.

In a further embodiment effective isomerization conditions involves atemperature in the interval 250-350° C., a pressure in the interval30-150 Bar, and a liquid hourly space velocity (LHSV) in the interval0.5-8 and wherein the material catalytically active in isomerizationcomprises one or more active metals in their active form taken from thegroup elemental platinum, elemental palladium, elemental nickel,sulfided nickel, sulfided cobalt, sulfided tungsten and sulfidedmolybdenum, one or more acidic supports, preferably molecular sieves,such as those having a topology taken from the group comprising MFI,FAU, BEA, MOR, FER, MRE, MWW, AEL, TON and MTT and an amorphousrefractory support comprising one or more oxides taken from the groupcomprising alumina, silica and titania. This has the associated benefitof such process conditions and catalytically active materials beinghighly suited for efficient conversion of especially pseudocumene tomesitylene. Typically, the amount the amount of psedocumene in saidisomerized hydrocarbon stream is reduced by at least 20% wt, 50% wt or80% wt or more compared to said intermediate boiling hydrocarbonfraction.

A further aspect of the present disclosure relates to a process forproduction of a synthetic gasoline product from a feedstock comprisingmethanol, said process comprising the steps of;

-   -   A. directing a stream comprising methanol to contact a material        catalytically active in methanol to gasoline conversion        providing a raw synthetic gasoline,    -   B. stabilizing said raw synthetic gasoline by separating a        fraction boiling below 40° C. from the raw synthetic gasoline,        thereby providing a synthetic hydrocarbon mixture    -   C. directing said synthetic hydrocarbon mixture to react        according to a method according to a previous aspect or        embodiment.

This has the associated benefit of such a process making an efficientconversion of methanol to a synthetic gasoline matching strictrequirements to distillation curve specifications.

A further aspect of the present disclosure relates to a gasolinepost-treatment unit for combining and post-treating two streams ofsynthetic hydrocarbons, a low boiling hydrocarbon inlet, comprising anintermediate boiling hydrocarbon inlet and an upgraded syntheticgasoline product outlet, an post-treatment hydrocracking unit, having aninlet and an outlet and a hydrogenation unit having an inlet and anoutlet, wherein the intermediate boiling hydrocarbon inlet is in fluidcommunication with said post-treatment hydrocracking unit inlet and saidpost-treatment hydrocracking unit outlet is in fluid communication witheither said hydrogenation unit inlet or said upgraded synthetic gasolineproduct outlet, and said low boiling hydrocarbon inlet is in fluidcommunication with said hydrogenation unit inlet and the hydrogenationunit outlet is in fluid communication with the upgraded syntheticgasoline product outlet. This has the associated benefit of such agasoline upgrading unit being flexible and efficient for provision of asynthetic gasoline in compliance with the strict or intermediatespecifications as required.

A further aspect of the present disclosure relates to a process plantfor production of a synthetic gasoline product comprising a gasolinepost-treatment unit according to the previous aspect, and a hydrocarbonsynthesis section having an oxygenate inlet and a synthetic hydrocarbonoutlet, a gasoline splitter section, having an inlet and at least a lowboiling hydrocarbon outlet, an intermediate boiling hydrocarbon outletand a high boiling hydrocarbon outlet and a hydrocracking section havingan inlet and an outlet, and an optional isomerization section having aninlet and an outlet, wherein the gasoline splitter section inlet is influid communication with the synthetic hydrocarbon outlet, wherein ifthe optional isomerization section is absent, the intermediate boilinghydrocarbon outlet is in fluid communication with the low boilinghydrocarbon inlet of the gasoline post-treatment unit or wherein if theoptional isomerization section is present, the intermediate boilinghydrocarbon outlet is in fluid communication with the inlet of theoptional isomerization section and the outlet of the optionalisomerization section is in fluid communication with the low boilinghydrocarbon inlet of the gasoline post-treatment unit, wherein the highboiling hydrocarbon outlet is in fluid communication with thehydrocracking section inlet and the hydrocracking section outlet is influid communication with the gasoline splitter section inlet, or influid communication with a further means of separation having an highboiling hydrocarbon outlet in fluid communication with the gasolinesplitter section inlet and an intermediate boiling hydrocarbon outlet influid communication with either the intermediate boiling hydrocarbonoutlet of the gasoline splitter section or the intermediate boilinghydrocarbon inlet of the gasoline post-treatment unit.

This has the associated benefit of such a process making an efficientconversion of methanol to a synthetic gasoline matching strictrequirements to distillation curve and olefin concentrationspecifications.

In a further embodiment an intermediate boiling fraction being an amountof the synthetic hydrocarbon mixture, is directed to contact a materialcatalytically active in isomerization under effective isomerizationconditions, and wherein the intermediate boiling hydrocarbon fractioncontains at least 80% of the molecules comprising exactly 9 carbon atomsof the synthetic hydrocarbon mixture with the associated benefit of sucha process increasing the octane number of the synthetic hydrocarbonmixture, by conversion of pseudocumene to mesitylene.

In a further embodiment the aromatics comprising 10 or more carbon atomsin the intermediate boiling fraction accounts for less than 5%, 10% or20% of the aromatics comprising 10 or more carbon atoms in the synthetichydrocarbon mixture, with the associated benefit that when a minimum ofC10+ aromatics are present in the intermediate boiling fraction, amajority is present in the high boiling hydrocarbon fraction such thatthe selective separation maximizes the amount of high boilinghydrocarbons to undergo hydrocracking.

The conversion of methanol or methanol/dimethyl ether mixtures intogasoline is generally referred to as the Methanol-to-Gasoline (MTG)process. In this process the methanol reactant is typically synthetizedfrom a synthesis gas, which may be made by gasification of solidcarbonaceous material or by reforming liquid or gaseous hydrocarbons,typically natural gas. The gasoline synthesis takes place in well-knownfixed bed and/or fluidized bed reactors and is typically carried out ata pressure of 10-40 bar and a temperature of 280-450° C., preferably300-430° C. The effluent from the gasoline synthesis section, which isenriched in gasoline components and water, low boiling olefinichydrocarbons, methane and paraffins, is cooled and passed to a threephase separating unit where a non-polar phase comprising C3+hydrocarbons (including paraffins, naphthenes, aromatics and olefins), apolar phase comprising water, oxygenated hydrocarbon by-products andunconverted oxygenates, and a gaseous phase comprising uncondensables(H₂, CO, CO₂ etc.), light ends (CH₄, C₂H₆) and low boiling olefins areseparated. The gaseous phase is normally split in a purge stream and arecycle stream directed for the production of synthesis gas.

Raw synthetic gasoline is typically fed to a degassing unit to removefuel gas and LPG fraction and volatile by-products dissolved in the rawsynthetic gasoline, to provide a stabilized synthetic gasoline. Thisdegassing unit may be either independent or integrated into other meansof separation for the synthetic gasoline.

Although the conversion of methanol or methanol/dimethyl ether mixturesinto gasoline is generally referred to as the Methanol-to-Gasolineprocess, oxygen-containing hydrocarbons (oxygenates) other than methanolare also easily converted in the MTG process. Apart from the desiredportion of especially C₅₊ gasoline products and co-produced water,gasoline synthesis results in some by-production of olefins, paraffins,methane and products from thermal cracking (hydrogen, CO, CO₂).Subsequent separation and/or distillation ensures the upgrading of theraw hydrocarbon product mixture to useful gasoline. Naturally, a highyield of the useful gasoline products is desirable for obtaining properprocess economy.

The synthesis gas for reacting to form the reactive oxygenates for theMTG process, may be made any by synthesis gas production processes wellknown to the skilled person. These processes may involve gasification ofcarbonaceous materials, such as coal, (typically high boiling)hydrocarbons, solid waste and biomass; from reforming of liquid orgaseous hydrocarbons, typically natural gas; from coke oven waste gas;from biogas or from combination of streams rich in carbon oxides andhydrogen—e.g. of electrolytic origin. When the oxygenates originatesfrom biomass, they may be created by synthesis or fermentation and theymay be characterized by having a 14C-isotope content above 0.5 parts pertrillion of the total carbon content. Oxygenates originating frombiomass will be beneficial due to a reduced CO₂ emission.

The synthesis section for the production of easily convertibleoxygenates may consist of a one-step methanol synthesis, a two-stepmethanol synthesis, a two-step methanol synthesis followed by a DMEsynthesis, or a methanol synthesis step followed by a combined methanoland DME synthesis step and a DME synthesis step or a one-step combinedmethanol and DME synthesis. It would be understood that the number ofpossible combinations of means of co-feeding into the methanol/DMEsynthesis loop and the layouts of the methanol or methanol/dimethylether synthesis is large. Any combinations deductible is therefore to beregarded as embodiments of present invention.

A catalytically active material comprising a zeolite is used for theconversion of oxygenates to gasoline products. This may be any zeolitetype being known as useful for the conversion of oxygenates to gasolinerange boiling hydrocarbons. Preferred types are those with a silica toalumina mole ratio of at least 12 and pore sizes formed by up to 12membered rings, preferably 10 membered. Examples of such zeolites arethose having one of the topologies MFI, MEL, MTW, MTT, FER such asZSM-5, ZSM-11, ZSM-12, ZSM-23, ZSM-35 and ZSM-38. The manufacture ofthese is well known in the art and the catalysts are commerciallyavailable. A common catalytically active material is the ZSM-5 zeolitein its hydrogen form, i.e. HZSM-5.

Without being bound by theory, the synthesis of gasoline from oxygenatesis in simple terms based on conversion of some methanol (a C1 compound)to dimethylether (a C2 compound). Methanol (C1) and dimethylether (C2)react to form olefins (C2-C5), and the olefins react to form aromaticsand naphthenics (C6-C11+) as well as longer olefins and paraffins(C6-C11). The gaseous compounds (C1-C3) are recycled to synthesis gasproduction and the high boiling compounds constitute a mixturecorresponding qualitatively to fossil naphtha. As the catalyst isdeactivated, synthesis temperature is increased and as a result therelative activity of side reactions towards forming longer olefins isincreased.

While functionally equivalent, to naphtha obtained by hydroprocessing offossil hydrocarbons, the synthetic gasoline has a different carbondistribution, resulting into a slightly higher boiling range ofproducts, typically with a lower amount of C6 and C7 hydrocarbons, ahigher amount of C8, C9 and C10 hydrocarbons as well as a presence ofC11+ hydrocarbons in the 2-5 wt % range, which would be substantiallyabsent in fractionated fossil hydrocarbons. A further difference betweenthe nature of fossil gasoline and synthetic gasoline is the fact thatfossil gasoline is a mixture of hundreds of different molecules, whereassynthetic gasoline is dominated by as few as 10 different molecules thataccount for approximately 50 wt % of the total composition. The natureof the synthetic gasoline is illustrated in Table 1.

A common C10 hydrocarbon in the synthetic gasoline product is durene(1,2,4,5-tetramethylbenzene), which has a melting point of 79.2° C. anda boiling point of 196° C. The high melting point is problematic for thefinal gasoline product, especially in cold climates. The othertetramethylbenzenes have a much lower melting point and a slightlyhigher boiling point.

Among the C9 hydrocarbons in the synthetic gasoline product,pseudocumene (1,2,4-trimethylbenzene) is the most abundant, whereas theisomer mesitylene (1,3,5-trimethylbenzene) is less common. The octanenumber of mesitylene is 171, i.e. higher than the octane number of 148for pseudocumene but the melting point and boiling points are similar(mesitylene/pseudocumene m.p. of −45/−44° C. and b.p. of 165/169° C.,respectively).

The C11+ hydrocarbons are often diaromatics and are undesired ingasoline due to the potential formation of particulate matter duringcombustion.

As shown in Table 1, an inherent product group in the synthesis ofgasoline from methanol is olefins. The majority of olefins will be C7and C8 compounds. Typically, around 6-15 wt % olefins are produced,which is in compliance with typical intermediate specification, but notin compliance with strict specifications.

A synthetic gasoline product with lower content of C8+ compounds wouldthereforebe preferable, as the resulting boiling point distributionwould be in compliance with strict specifications, and a simple solutionensuring compliance with all current gasoline standards would be aseparation of C8+ products and directing these to other uses.Unfortunately, the chemical nature of the C8+ fraction is not favorablefor alternative valuable use, and therefore the use would typically todirect this fraction for use in fired heaters or for recycle to be usedin the synthesis gas. Since this would constitute a yield loss of atleast 20% this is not a desirable solution.

An aspect to keep in mind when considering the product composition ofthe MTG process, is that the MTG synthesis process results in a morehomogeneous product composition, contrary to fossil gasoline. This haspractical implications, e.g. on the separation processes, where thedistillation curve for synthetic gasoline is not semi-continuous as forfossil feedstocks, and therefore the manipulation by fractionation isless flexible for synthesized gasoline compared to fossil gasoline, suchthat even a minor shift of fractionation temperature may result in adramatic shift in the fraction withdrawn.

Instead of separation, selective catalytic upgrading, especially of theC8+ fraction may be considered, and efficient means for that includeisomerization, hydrocracking and saturation of olefins.

Isomerization is the conversion of constituents into other constituenthaving the same molecular formula. The objective of isomerization is toconvert undesired constituents to desired constituent, e.g. conversionof pseudocumene to mesitylene and durene to isodurene

An isomerization process for the combined conversion of pseudocumene tomesitylene and durene to isodurene was proposed in WO2013/178375 A1.This process involves treating a high boiling fraction of the syntheticgasoline over a sulfided nickel isomerization catalyst comprising azeolite of the MFI topology such as ZSM-5, which improved octane numbersas well as cold flow properties by an increased selectivity forfavorable isomerization over a non-sulfided catalyst.

This isomerization process will however not solve the problem of strictspecification for the distillation curve since the products ofisomerization will boil at similar temperatures as the parent molecule.C11+ compounds, which are the main constituents of the distillation tailof the synthetic gasoline, are typically not converted to lower boilingproducts at the isomerization conditions in WO2013/178375 A1.

In a more general perspective, the material catalytically active inisomerization of synthetic gasoline typically comprises an active metal(which according to the present disclosure is preferred to be eithersulfided base metals such as nickel, cobalt, tungsten and/or molybdenumalone or in combination or one or more elemental reduced metals such asnickel, platinum and/or palladium), an acidic support (typically amolecular sieve showing high shape selectivity, and having a topologysuch as MFI, FAU, BEA, MOR, FER, MRE, MWW, AEL, TON and MTT) and atypically amorphous refractory support (such as alumina, silica ortitania, or combinations thereof). Specific examples are materialcatalytically active in isomerization comprising sulfided or reduced Niin combination with ZSM-5, reduced Ni in combination withsilica-alumina, sulfided NiW in combination with γ-alumina, reduced Ptin combination with ZSM-5, reduced Pt in combination with zeolite Y, allsupported on an amorphous material, such as alumina. The catalyticallyactive material may comprise further components, such as boron orphosphorous.

Effective isomerization conditions typically involve directing theintermediate synthetic gasoline fraction to contact a materialcatalytically active in isomerization under effective isomerizationconditions. The conditions are typically a temperature in the interval250-430° C., a pressure in the interval 50-100 Bar, and a liquid hourlyspace velocity (LHSV) in the interval 0.3-8. Increasing temperature ordecreasing LHSV will, as it is known to the skilled person, increase theprocess severity and thus the isomerization conversion. Isomerization issubstantially thermally neutral and consumes only hydrogen inhydrocracking side reactions so only a moderate amount of hydrogen isadded in the isomerization reactor. If the active metal on the materialcatalytically active in isomerization is in elemental form, theisomerization feedstock must only comprise potential catalyst poisons inlow levels such as levels of sulfur below 50 ppmw or even 1-10 ppmw,which may require purification. If the active metal is in sulfided form,a level of sulfur above 50 ppmw is required.

The T₉₀ requirements may be met by converting the high boiling fractionof synthetic gasoline to a lower boiling fraction by catalytichydrocracking. Such a process will convert at least an amount of thedi-aromatics to mono-aromatics and dealkylate multi-substitutedmonoaromatics to lower boiling compounds, thus reducing the intermediateboiling point and high boiling point of the product distillation curve.The initial boiling point (IBP) of the high boiling fraction that willbe selectively hydrocracked is selected/determined according to anoptimization of the conversion required to meet distillation pointsspecifications whilst minimizing octane rating loss incurred bydealkylation and hydrogenation reactions.

Hydrocracking involves directing high boiling synthetic gasolinefraction to contact a material catalytically active in hydrocracking.The material catalytically active in hydrocracking typically comprisesan active metal (which may be one or more sulfided base metals such asnickel, cobalt, tungsten and/or molybdenum or reduced noble metals suchas Pt, Pd or PdPt), an acidic support (typically a molecular sieveshowing high cracking activity, and having a topology such as MF, BEA,FAU and MOR, but amorphous acidic oxides such as silica-alumina may alsobe used) and a refractory support (such as alumina, silica or titania,or combinations thereof). The catalytically active material may comprisefurther components, such as boron or phosphorous.

Effective hydrocracking conditions are typically a temperature in theinterval 250-430° C., a pressure in the interval 20-100 Bar, and aliquid hourly space velocity (LHSV) in the interval 0.3-10. Increasingtemperature or decreasing LHSV will, as it is known to the skilledperson, increase the process severity and thus the hydrocrackingconversion, i.e. the amount of product having a lower molecular weightthan the feedstock. As hydrocracking is exothermic, the process mayinvolve intermediate cooling e.g. by quenching with cold hydrogen, feedor product. A high boiling synthetic gasoline fraction, including thetreat gas, is typically directed to contact the material catalyticallyactive in hydrocracking without further purification. When the activemetal(s) on the material catalytically active in hydrocracking are basemetals, this mixture of hydrocarbons and treat gas should preferablycontain at least 50 ppmw sulfur and when it is a noble metal the sulfurlevel should preferably be below 10 ppmw sulfur.

As shown, olefins may be present in too high concentration in the rawsynthetic gasoline. They may be removed by a catalytic hydrogenationprocess, where hydrogen reacts with the olefin to saturate olefinicdouble bonds.

The material catalytically active in hydrogenation of olefins typicallycomprises an active metal (sulfided base metals such as nickel, cobalt,tungsten and/or molybdenum, but possibly also either elemental noblemetals such as platinum and/or palladium) and a refractory support (suchas alumina, silica or titania, or combinations thereof). The most commoncatalytically active materials will be sulfided molybdenum (5-20 wt %)and nickel (1-10 wt %) on an alumina support.

Effective hydrogenation conditions are typically a temperature in theinterval 220-350° C., a pressure in the interval 10-150 Bar, and aliquid hourly space velocity (LHSV) in the interval 0.1-10, optionallytogether with intermediate cooling by quenching with cold hydrogen, feedor product.

Hydrogenation of olefins will typically also occur in contact withmaterials catalytically active in other hydroprocessing reactions suchas hydrocracking and isomerization, under the conditions for theseprocesses.

Some embodiments of the present disclosure, may involve the use of acatalytically active material comprising a sulfided base metal. In suchembodiments, addition of a sulfur donor is required to maintainsulfidation, and thus activity, of the sulfided active metal, since thesynthetic gasoline is inherently sulfur free. Similarly, embodiments maybe envisioned in which such added sulfur must be removed upstream acatalytically active material based on noble metals. Typically sulfurremoval will occur in relation to stabilization of intermediateproducts.

A process plant for upgrading of synthetic gasoline to comply withintermediate specifications for T₉₀ and olefin content will, asmentioned above, beneficially involve a single intermediate productfractionation distributing product between the different treatments,such that C10+ will be directed to hydrocracking and C9 toisomerization, in order to adjust boiling point and boost the octanenumber, while lower boiling hydrocarbons will be by-passed suchreactions to ensure a minimal yield loss.

A process for providing a product which is compatible with strictspecifications would also require hydrocracking and isomerization aswell as some olefin hydrogenation of the synthetic gasoline. Asmentioned hydrogenation of olefins will also occur under the reactionconditions for isomerization. Conveniently the C9+ fraction wouldrequire hydrocracking and the C7 fraction (or at least a part of it) andthe C8 fraction would contain a high amount of olefins to be saturated,and therefore a simple process for compliance with strict specificationswith a low number of reactors would involve splitting the syntheticgasoline in a C3-C6/C7 fraction which is passed untreated as product, aC7/C8-C9 fraction for isomerization and hydrogenation and a C10+fraction for hydrocracking with recycle of the product.

By this process configuration flexibility is obtained in a simpleconfiguration. However, a detailed analysis of the process shows thatimplementing this configuration will having higher capital andoperational cost. Due to the increased process volume and relatedincreased gas flows the cost related to reactors and reactor internalsas well as compressors and other aspects of the process gas loop alsoincrease. An increase in make-up hydrogen addition will also benecessary. Therefore following this analysis a process configuration inwhich two extra reactors are provided downstream the processconfiguration complying with the intermediate specifications issurprisingly found to be more cost-effective.

According to such a process, the synthetic gasoline is split in a C3-C8fraction which is passed untreated as product, a C9+ fraction forisomerization and a C10+ fraction for hydrocracking with recycle of theproduct. The isomerized C9+ fraction is then further hydrocracked andcombined with the C3-C8 fraction, the combined stream is subsequentlydirected for olefin saturation. While such a process has the added costof two reactors, the total volume of reactors and the total volume ofcatalyst required is reduced, with substantial savings as the result.

FIGURES

FIG. 1 shows a process for producing a synthetic gasoline productcomprising a gasoline upgrade unit according to the present disclosureFIG. 2 shows a process for producing a synthetic gasoline, in whichgasoline is upgraded without a separate gasoline upgrade unit by aprocess integrated in the gasoline stabilization unit.

FIG. 1 shows an embodiment of the present disclosure, which isconfigured for providing a synthetic gasoline complying with strictspecifications for boiling point and olefin content, while alsominimizing loss of octane number rating by inclusion of an isomerizationunit, and for maximizing the gasoline yield by a low extent ofhydrocracking per pass in combination with recycling the hydrocrackedhigher boiling hydrocarbon fraction. Here a carbonaceous feed stream(2), typically natural gas, but optionally a solid feedstock such ascoal or renewable feedstock, is directed to a methanol front-end processunit (MFP). For solid feedstock, a gasifier will produce a synthesisgas, whereas natural gas is converted to synthesis gas in a reformer.The synthesis gas is cleaned, and the composition may be adjusted tomatch the requirements of a downstream methanol synthesis unit, in whichsynthesis gas is catalytically converted to methanol. The producedmethanol (4) is directed to a hydrocarbon synthesis unit (MTG) in whichmethanol (4) is converted to a raw synthesized hydrocarbon mixture (6).The raw synthesized hydrocarbon mixture (6) is directed to gasolinetreatment unit (GTU) comprising a gasoline splitter section (GSS), whichmay comprise several sub-units, typically including a three-phaseseparator, separating incondensable gases, water and raw syntheticgasoline. The raw hydrocarbon mixture (6) is typically stabilized in ade-ethanizer and an LPG splitter, to provide one or more gaseoushydrocarbon streams and a synthesized hydrocarbon mixture. Forsimplicity the figure does not show withdrawal of one or more gasstreams comprising H₂, CO, CH₄, C₂H₆, C₃H₈, C₄H₁₀, and to some extent,C₅H₁₂, but in practice it is typically split in multiple fractions asdescribed. The gasoline splitter section (GSS) further splits thesynthesized hydrocarbon mixture in a low boiling hydrocarbon fraction(10) boiling in the gasoline range, and typically comprising C4-C8hydrocarbons, an intermediate boiling hydrocarbon fraction (12),typically dominated by C9 hydrocarbons and a higher boiling hydrocarbonfraction (14) comprising C10+ hydrocarbons.

The intermediate boiling hydrocarbon fraction (12) is directed to ahydroisomerization unit (ISOM), in which pseudocumene is converted tomesitylene, resulting in increased octane number providing an isomerizedintermediate boiling hydrocarbon fraction (16). The higher boilinghydrocarbon fraction (14) is directed to a hydrocracking unit (HDC), inwhich the C10+ hydrocarbons are converted mainly to C8-C9 hydrocarbonsby hydrocracking, providing a hydrocracked higher boiling hydrocarbonfraction (18). The hydrocracked higher boiling hydrocarbon fraction (18)is directed to feed the gasoline splitter section (GSS), such that lightand intermediate boiling hydrocracked products are directed to the lowboiling hydrocarbon fraction (10) and intermediate boiling hydrocarbonfraction (12), whereas the higher boiling hydrocracked products aredirected to the higher boiling hydrocarbon fraction (14), and thusrecycled to the inlet of the hydrocracking unit (HDC), allowing milderhydrocracking conditions per pass, as any unconverted high boilinghydrocarbons will be recycled.

During production of strict specification gasoline, the low boilinghydrocarbon fraction (10) and the isomerized intermediate boilinghydrocarbon fraction (16) will be directed to a gasoline post-treatmentunit (GPT) which may be integrated into the gasoline treatment unit(GTU) or be positioned separately, and possibly receive additional feedstreams. The gasoline post-treatment unit (GPT) will contain anpost-treat hydrocracker unit (PHC) containing a material catalyticallyactive in hydrocracking, which may be the same or different from thematerial catalytically active in hydrocracking in the hydrocracker unit(HDC) and a hydrogenation unit (HYD) containing a material catalyticallyactive in hydrogenation of olefins.

The post-treat hydrocracker unit (PHC) will receive the stream ofisomerized intermediate boiling hydrocarbon fraction (16), and beconfigured for an appropriate conversion, resulting in the boiling pointbeing reduced to the extent required for compliance with specifications,to provide a hydrocracked isomerized hydrocarbon fraction (20), whichwithout removal of gas phase including hydrogen is combined with the lowboiling hydrocarbon fraction (10) and directed to the hydrogenation unit(HYD) for partial or complete saturation of olefins.

During production of intermediate specification gasoline, the lowboiling hydrocarbon fraction (10) and the isomerized intermediateboiling hydrocarbon fraction (16) may be combined, to provide asynthetic gasoline product (24), to reduce process complexity andoperating cost.

Hydrogen is added to the hydrocracking, isomerization and hydrogenationunits, and the products therefrom are typically stabilized in aseparator, by withdrawing light gases but for simplicity this is notshown.

FIG. 2 shows a process, which is configured for providing a syntheticgasoline complying with strict specifications for boiling point andolefin content, while also minimizing loss of octane number rating, byinclusion of an isomerization unit, and for maximizing the gasolineyield by a low extent of hydrocracking per pass in combination withrecycling the hydrocracked higher boiling hydrocarbon fraction. Here acarbonaceous feed stream (2), typically natural gas, but optionally asolid feedstock such as coal or renewable feedstock, is directed to amethanol front-end process unit (MFP). For solid feedstock, a gasifierwill produce a synthesis gas, whereas natural gas is converted tosynthesis gas in a reformer. The synthesis gas is cleaned, and thecomposition may be adjusted to match the requirements of a downstreammethanol synthesis unit, in which synthesis gas is catalyticallyconverted to methanol. The produced methanol (4) is directed to ahydrocarbon synthesis unit (MTG) in which methanol is converted to a rawsynthesized hydrocarbon mixture (6). The raw synthesized hydrocarbonmixture (6) is directed to gasoline treatment unit (GTU) comprising agasoline splitter section (GSS), which may comprise several sub-units,typically including a three-phase separator, separating incondensablegases, water and raw synthetic gasoline. The raw hydrocarbon mixture istypically stabilized in a de-ethanizer and an LPG splitter, to provideone or more gaseous hydrocarbon streams and a synthesized hydrocarbonmixture. For simplicity the figure does not show withdrawal of a gasstream comprising H₂, CO, CH₄, C₂H₆, C₃H₈, and C₄H₁₀, but in practice itis typically split in multiple fractions as described. The gasolinesplitter section (GSS) further splits the synthesized hydrocarbonmixture in three fractions, although a higher number of fractions may beprovided. When producing synthetic gasoline (24) according tointermediate specifications, the split will be in a low boilinghydrocarbon fraction (10) typically comprising C4-C8 hydrocarbons, anintermediate boiling hydrocarbon fraction (12), typically dominated byC9 hydrocarbons and a higher boiling hydrocarbon fraction (14)comprising C10+ hydrocarbons. When producing synthetic gasoline (24)according to strict specifications, the gasoline splitter section (GSS)may also be configured such that the low boiling hydrocarbon fraction(10) comprises C4-C7 hydrocarbons, the intermediate boiling hydrocarbonfraction (12), comprises some C7 and C10 as well as the majority of C8and C9 hydrocarbons and a higher boiling hydrocarbon fraction (14)comprising C10+ hydrocarbons, which would be the gasoline splitconfiguration chosen for compliance with strict specifications.

The intermediate boiling hydrocarbon fraction (12) is directed to ahydroisomerization unit (ISOM), in which pseudocumene is converted tomesitylene and olefins are partially hydrogenated, resulting inminimization of loss of octane number and providing an isomerizedintermediate boiling hydrocarbon fraction (16). The higher boilinghydrocarbon fraction (14) is directed to a hydrocracking unit (HDC), inwhich the C10+ hydrocarbons are converted mainly to C8-C9 hydrocarbonsby hydrocracking, providing a hydrocracked higher boiling hydrocarbonfraction (18). The hydrocracked higher boiling hydrocarbon fraction (18)is directed to feed the gasoline splitter section (GSS), such that lowboiling and intermediate boiling hydrocracked products are directed tothe low boiling hydrocarbon fraction (10) and intermediate boilinghydrocarbon fraction (12), whereas the higher boiling hydrocrackedproducts are directed to the higher boiling hydrocarbon fraction (14),and thus recycled to the inlet of the hydrocracking unit (HDC), allowingmilder hydrocracking conditions per pass, as any unconverted highboiling hydrocarbons will be recycled. The low boiling hydrocarbonfraction (10), the isomerized intermediate boiling hydrocarbon fraction(16) and the hydrocracked higher boiling hydrocarbon fraction (18) arecombined, to provide a synthetic gasoline product (24).

As for FIG. 1 , hydrogen is added to the hydrocracking and isomerizationunits, and the products therefrom are typically stabilized in aseparator, by withdrawing light gases but for simplicity this is notshown.

In all embodiments shown, the hydrocracking unit (HDC) contains amaterial catalytically active in hydrocracking and is operated underhydrocracking conditions. If the material catalytically active inhydrocracking comprises sulfided base metals, a source of sulfur must bepresent, typically by addition of a sulfur containing hydrocarbon. Ifthe material catalytically active in hydrocracking comprises reducedmetals, the fractions of the synthetic gasoline are inherentlysulfur-free, and thus, do not require any sulfur removal process. If norecycle is applied, the process may typically be configured for a highhydrocracking conversion of higher boiling hydrocarbon to ensure thatthe product complies with the relevant requirements, whereas the processmay be configured for low or moderate hydrocracking conversion ifrecycle is applied.

Similarly, the hydroisomerization unit (ISOM), if present, contains amaterial catalytically active in hydroisomerization and is operatedunder hydroisomerization conditions. If the material catalyticallyactive in hydroisomerization comprises sulfided base metals, a source ofsulfide must be present in the intermediate boiling hydrocarbonfraction, typically by addition of a sulfur containing hydrocarbon. Ifthe material catalytically active in hydroisomerization comprisesreduced metals, the process must be designed to remove sulfides from theintermediate boiling hydrocarbon fraction, at least to a level below 50ppmw, which may be accomplished during the stabilization of thesynthetic gasoline in the hydrocracker section (HDC) or in the gasolinesplitting section (GSS).

EXAMPLES

A process for production of synthetic gasoline via a methanol route wasevaluated by experimental testing of stabilized synthetic gasolinehaving the composition and characteristics shown in Table 1. Thisproduct is neither in compliance with the strict specifications orintermediate specifications considered, which for the examples are anupper limit for T₉₀ of 152° C. (305° F.) and less than 6 vol % olefinsafter blending with 10% ethanol (which before blending corresponds to6.6 vol %, or 6 wt % in the synthetic gasoline) in strict specificationsand T₉₀ of 168° C. (335° F.) and less than 10 vol % olefins afterblending with 10% ethanol (which before blending corresponds to 11 vol%, or 10 wt % in the synthetic gasoline) in intermediate specifications.

The examples assume final production of 100 t/h synthetic gasoline.

Example 1

Example 1 is an example according to FIG. 2 . Here a synthetic gasolineis produced, which in a gasoline splitter is split in a low boilingfraction (C3-C8, boiling below 150° C.), an intermediate fraction(C9-C10, boiling between 150° C. and 180° C.) and a high boilingfraction (C9+, boiling above 180° C.). The high boiling fraction ishydrocracked and directed to the gasoline splitter. The intermediateboiling fraction is isomerized and directed to be combined with the lowboiling fraction.

By this separation the majority of the synthetic gasoline is directed tothe low boiling fraction (80 t/h), with minor volumes in theintermediate fraction (20 t/h) and high boiling fraction (7 t/h), all ofwhich is recycled.

According to this example, the concentration of olefins is 10 wt % andT90 is 168° C., which is in compliance with intermediate specificationsbut not in compliance with strict specifications.

Example 2

Example 2 is also an example according to the process layout FIG. 2 ofthe present disclosure, but with different fractionation temperatures.Here a synthetic gasoline is produced, which in a gasoline splitter issplit in a low boiling fraction (41 t/h, C3-C7, boiling below 90° C.),an intermediate fraction (59 t/h, C8-C9, boiling between 90° C. and 150°C.) and a high boiling fraction (13 t/h, C10+, boiling above 150° C.).The high boiling fraction is hydrocracked and directed to the gasolinesplitter. The intermediate boiling fraction is isomerized and directedto be combined with the low boiling fraction.

In this example, the volume of the intermediate stream is increased from22 t/h to 59 t/h, i.e. a factor 2.7 compared to example 1 and the volumedirected for hydrocracking is increased from 10 t/h to 14 t/h, i.e. by40%. To have isomerization conversion similar to Example 1, similarreaction conditions are required, including reactor space velocity.Therefore, an increase of the isomerization reactor size by a factor 2.7is necessary for sufficient isomerization. It is not assumed thatadditional reactor volume or catalyst is required due to the olefinsaturation. The volume directed for hydrocracking will also be increasedby 40%. In addition, there will be two additional HDC catalyst beds,reactor size must be increased and the volume of make-up hydrogenconsumed will be increased, which will add to capital cost as well asoperational cost.

According to this example, the concentration of olefins is 6 wt % andT90 is 152° C., which is in compliance with strict specifications.

Example 3

Example 3 is an example according to FIG. 1 of the present disclosure.Here a synthetic gasoline is produced, which is split in a low boilingfraction (C3-C8, boiling below 150° C.), an intermediate fraction(C9-C10, boiling between 150° C. and 180° C.) and a high boilingfraction (C9+, boiling above 180° C.), in a similar manner as Example 1(78 t/h, 22 t/h and 10 t/h respectively).

The majority of the synthetic gasoline is directed to the low boilingfraction, with minor volumes in the intermediate fraction and highboiling fraction, and thus the required isomerization is possible withan isomerization reactor of the same size as in Example 1. However, toobtain the appropriate boiling point, hydrocracking is carried out onthe isomerized intermediate fraction and hydrogenation is carried out onthe full product fraction. The required volumes of the hydrocrackingreactor and the isomerization reactor are unchanged in comparison withExample 1, gas flows will also be unchanged and hydrogen consumptionwill only increase slightly. Compared to Example 1 and Example 2,Example 3 requires two extra reactors; a post-treat hydrocracking unitand a hydrogenation unit:

but the related capital cost is secondary to the cost related to theextra reacting volumes of Example 2.

According to this example, the concentration of olefins is 4 wt % andT90 is 152° C., which is in compliance with strict specifications.

In comparison, of the three examples only Example 2 and Example 3 are incompliance with the strict specification. Example 2 is conceptuallysimilar to Example 1, and appears simpler, and requires 2 reactors less,and therefore appears the immediate choice.

Example 3 is however able to demonstrate the same performance as Example2, and although apparently more complex, Example 3 is also lessexpensive to implement, as the total volume of reacting streams will belower, and provides the flexibility of producing products adhering tostrict or intermediate specifications.

TABLE 1 Composition % (wt) Olefins % wt C5 12.8 1.4 C6 17.7 1.8 C7 14.32.1 C8 18.1 1.9 C9 17.3 0.5 C10 10.7 0.3 C11+ 1.6 0.0 n-Parafinic 0.9Iso-parafinic 6.5 Olefinic 1.3 Naphthenic 3 Aromatic 84.7

TABLE 2 Stream# 10 12 14 16 24 t/h 78 22 10 22 100 C5-C7 % wt 61 92C8-C9 % wt 39 65 65 C10+ % wt 35 98 35 7 Olefin % wt 12 2 0 2 10

TABLE 3 Stream# 10 12 14 16 24 t/h 41 59 14 59 100 C5-C7 % wt 100 14 1894 C8-C9 % wt 78 14 74 C10+ % wt 8 86 8 5 Olefin % wt 10 10 0 3 6

TABLE 4 Stream# 10 12 14 16 20 22 24 t/h 78 22 10 22 22 100 100 C5-C7 %wt 61 15 59 59 C8-C9 % wt 39 65 65 61 36 36 C10+ % wt 35 98 35 24 5 5Olefin % wt 12 2 0 2 2 10 4

1. A method for providing a synthetic gasoline product from a firstsynthetic hydrocarbon mixture produced from a mixture of reactiveoxygenates, said first synthetic hydrocarbon mixture having T90 of lessthan 140° C. and comprising at least 6 vol % or 11 vol % of olefins anda second synthetic hydrocarbon mixture, produced from a mixture ofreactive oxygenates, said second synthetic hydrocarbon mixture havingT90 of more than 150° C. said method comprising the steps of: a.directing the second synthetic hydrocarbon mixture to contact a materialcatalytically active in hydrocracking under effective hydrocrackingconditions, to provide a hydrocracked second synthetic hydrocarbonmixture, and b. directing said first synthetic hydrocarbon mixture tocontact a material catalytically active in olefin hydrogenation, toprovide a hydrogenated hydrocarbon mixture, wherein said hydrocrackedsecond synthetic hydrocarbon mixture is either added to the firstsynthetic hydrocarbon mixture upstream contacting said materialcatalytically active in olefin hydrogenation or it is added tohydrogenated hydrocarbon mixture, downstream contacting said materialcatalytically active in olefin hydrogenation to provide said syntheticgasoline product comprising less than 6 vol % or 11 vol % olefins.
 2. Amethod for providing a synthetic gasoline product according to claim 1,wherein effective hydrocracking conditions involve a temperature in theinterval 250-425° C., a pressure in the interval 30-150 Bar, and aliquid hourly space velocity (LHSV) in the interval 0.5-4, optionallytogether with intermediate cooling by quenching with hydrogen, feed orproduct and wherein the material catalytically active in hydrocrackingcomprises (a) one or more active metals taken from the group platinum,palladium, nickel, cobalt, tungsten and molybdenum, (b) an acidicsupport showing cracking activity, and (c) a refractory support.
 3. Amethod for providing a synthetic gasoline product according to claim 1,wherein effective hydrogenation conditions involve a temperature in theinterval 220-350° C., a pressure in the interval 30-150 Bar, and aliquid hourly space velocity (LHSV) in the interval 0.5-4, optionallytogether with intermediate cooling by quenching with hydrogen, feed orproduct and wherein the material catalytically active in hydrocrackingcomprises 0.1% to 20% of one or more active metals taken from the groupplatinum, palladium, nickel, cobalt, tungsten and molybdenum and arefractory support.
 4. A method for providing a synthetic gasolineproduct according to claim 1, wherein said first synthetic hydrocarbonmixture and said second synthetic hydrocarbon mixture are provided byfractionation of a synthetic hydrocarbon mixture produced from a mixtureof reactive oxygenates, optionally after one or both synthetichydrocarbon mixtures having contacted a material catalytically active ina hydroprocessing process under active hydroprocessing conditions.
 5. Amethod for providing a synthetic gasoline product according to claim 4,wherein said fractionation provides a third synthetic hydrocarbonmixture, having a T90 above that of said second synthetic hydrocarbonmixture and wherein said third synthetic hydrocarbon mixture is directedto contact a material catalytically active in hydrocracking under activehydrocracking conditions, to provide a hydrocracked third synthetichydrocarbon mixture, which is included in said synthetic gasolineproduct, either by addition upstream said fractionation or by additionin a position downstream said fractionation.
 6. A method for providing asynthetic gasoline product from a synthetic hydrocarbon mixture producedfrom a mixture of reactive oxygenates comprising the steps of: i.fractionating the synthetic hydrocarbon mixture in at least a lowboiling hydrocarbon fraction and an intermediate boiling hydrocarbonfraction, ii. directing at least an amount of said intermediate boilinghydrocarbon fraction to contact a material catalytically active inisomerization under effective isomerization conditions to provide anisomerized intermediate boiling hydrocarbon fraction, iii. directing atleast an amount of said isomerized intermediate boiling hydrocarbonfraction to contact a material catalytically active in hydrocrackingunder effective hydrocracking conditions to provide a hydrocrackedintermediate boiling hydrocarbon fraction, and iv. combining at least anamount of said low boiling hydrocarbon fraction with said hydrocrackedintermediate boiling hydrocarbon fraction to provide a hydrogenationfeed stream and directing this hydrogenation feed stream to contact amaterial catalytically active in hydrogenation under effectivehydrogenation conditions providing a hydrogenated hydrocarbon productstream.
 7. A method for providing a synthetic gasoline product from asynthetic hydrocarbon mixture produced from a mixture of reactiveoxygenates according to claim 6, further comprising the steps of: v.further separating the synthetic hydrocarbon mixture in a higher boilingfraction comprising at least 70% of the molecules comprising 10 or morecarbon atoms present in the hydrocarbon mixture, vi. directing at leastan amount of said higher boiling hydrocarbon fraction as a hydrocrackingfeedstock to contact a material catalytically active in hydrocrackingunder effective hydrocracking conditions providing a hydrocrackedhydrocarbon stream, and vii. separating said hydrocracked hydrocarbonstream, in the same or an additional separation step, to provide a highboiling hydrocracked hydrocarbon stream and an intermediate boilinghydrocracked hydrocarbon stream, wherein at least an amount of saidintermediate boiling hydrocracked hydrocarbon stream, is added to atleast an amount of either said intermediate boiling hydrocarbon fractionor said isomerized intermediate boiling hydrocarbon fraction.
 8. Amethod for providing a synthetic gasoline product according to claim 7,wherein effective hydrocracking conditions involve a temperature in theinterval 250-425° C., a pressure in the interval 30-150 Bar, and aliquid hourly space velocity (LHSV) in the interval 0.5-4, optionallytogether with intermediate cooling by quenching with hydrogen, feed orproduct and wherein the material catalytically active in hydrocrackingcomprises (a) one or more active metals taken from the group platinum,palladium, nickel, cobalt, tungsten and molybdenum, (b) an acidicsupport showing cracking activity, and (c) a refractory support.
 9. Amethod for providing a synthetic gasoline product according to claim 6,wherein effective isomerization conditions involves a temperature in theinterval 250-350° C., a pressure in the interval 30-150 Bar, and aliquid hourly space velocity (LHSV) in the interval 0.5-8 and whereinthe material catalytically active in isomerization comprises one or moreactive metals in their active form taken from the group elementalplatinum, elemental palladium, elemental nickel, sulfided nickel,sulfided cobalt, sulfided tungsten and sulfided molybdenum, one or moreacidic supports, and an amorphous refractory support comprising one ormore oxides taken from the group comprising alumina, silica and titania.10. A process for production of a synthetic gasoline product from afeedstock comprising methanol, said process comprising the steps of: A.directing a stream comprising methanol to contact a materialcatalytically active in methanol to gasoline conversion providing a rawsynthetic gasoline, B. stabilizing said raw synthetic gasoline byseparating a fraction boiling below 40° C. from the raw syntheticgasoline, thereby providing a synthetic hydrocarbon mixture, and C.directing said synthetic hydrocarbon mixture to react according to amethod according to claim
 1. 11. A gasoline post-treatment unit forcombining and post-treating two streams of synthetic hydrocarbons, a lowboiling hydrocarbon inlet, comprising an intermediate boilinghydrocarbon inlet and an upgraded synthetic gasoline product outlet, anpost-treatment hydrocracking unit, having an inlet and an outlet and ahydrogenation unit having an inlet and an outlet, wherein theintermediate boiling hydrocarbon inlet is in fluid communication withsaid post-treatment hydrocracking unit inlet and said post-treatmenthydrocracking unit outlet is in fluid communication with either saidhydrogenation unit inlet or said upgraded synthetic gasoline productoutlet, and said low boiling hydrocarbon inlet is in fluid communicationwith said hydrogenation unit inlet and the hydrogenation unit outlet isin fluid communication with the upgraded synthetic gasoline productoutlet.
 12. A process plant for production of a synthetic gasolineproduct comprising a gasoline post-treatment unit according to claim 11,and a hydrocarbon synthesis section having an oxygenate inlet and asynthetic hydrocarbon outlet, a gasoline splitter section, having aninlet and at least a low boiling hydrocarbon outlet, an intermediateboiling hydrocarbon outlet and a high boiling hydrocarbon outlet and ahydrocracking section having an inlet and an outlet, and an optionalisomerization section having an inlet and an outlet, wherein thegasoline splitter section inlet is in fluid communication with thesynthetic hydrocarbon outlet, wherein if the optional isomerizationsection is absent, the intermediate boiling hydrocarbon outlet is influid communication with the low boiling hydrocarbon inlet of thegasoline post-treatment unit or wherein if the optional isomerizationsection is present, the intermediate boiling hydrocarbon outlet is influid communication with the inlet of the optional isomerization sectionand the outlet of the optional isomerization section is in fluidcommunication with the low boiling hydrocarbon inlet of the gasolinepost-treatment unit, wherein the high boiling hydrocarbon outlet is influid communication with the hydrocracking section inlet and thehydrocracking section outlet is in fluid communication with the gasolinesplitter section inlet, or in fluid communication with a further meansof separation having an high boiling hydrocarbon outlet in fluidcommunication with the gasoline splitter section inlet and anintermediate boiling hydrocarbon outlet in fluid communication witheither the intermediate boiling hydrocarbon outlet of the gasolinesplitter section or the intermediate boiling hydrocarbon inlet of thegasoline post-treatment unit.